Featured Puzzle: Pencils #1 – National Pencil Day

On this day in 1858, Hymen Lipman received US Patent # 19,783 for a pencil with an attached eraser. Sure, it was later rescinded because it wasn’t a new device, but just a composite of two existing products, but we still celebrate the day as National Pencil Day.

Much later, in 2017, a Japanese teenager submitted a new puzzle themed around pencils to Nikoli magazine that quickly gained popularity, because it seemed to capture the essence of solving pencil puzzles.

Draw pencils into the grid. Each pencil must also draw a line as long as itself, so that all grid cells are used.

• Pencils are 1-cell-wide rectangular regions of at least length 1, ending at the base of a tip (which doesn’t count toward the length).
• Cells with numbers must belong to a pencil of that length.
• Some pencils might contain more than one numbered cell. If so, they must be the same number.
• Not all tips are shown – you may discover extra pencils in the grid.
• Each pencil also draws a line, beginning at the tip, and extends a number of cells equal to the pencil length.
• Drawn lines travel in orthogonal directions that may have 90-degree turns. However, these lines may not cross themselves, a pencil, another tip, or any other line.
• All cells must belong to either a pencil, a line, or a tip.